Geologic Features Of Erdaohe Silver Polymetallic Deposit And Its Ore Finding Prediction In Middle Daxing'anling Mountains

Regional geotectonic position of Erdaohe Silver polymetal ore locate in the northwest of Erlian-Hegenshan-Arun Banner suture zone in middle section Daxing'anling Mountain, belong to Palaeozoic epicontinental hyperplasia in South east continental margin of Siberian plate, Mesozoic locate in the western margin of Daxing'anling Mountain Mesozoic volcano-magmatic belt, where is in circum-Pacific tectonic domain.Outcropped stratum mainly include Middle-Lower Ordovician Duobaoshan Formation,Middle and Upper Ordovician Luohe Formation and Upper Triassic Manketou'ebo formation in the workspace.Mainly developing medium-fine grained moyite in Middle Permian and fine grained diorite in Late Permian. Subject of tectonic line is in the north-eastern direction, folds and fractures are both development. Lead-zinc-silver-copper ore body have been discovered forty-two strip incentral workspace, strictly controlled by NE-trending structure, en echelon arrayed from north east south west direction. Metallic mineral mainly has blende?galena?pyrite,secondly has a little pyrite?magnetite?copper pyrites. Nonmetallic mineral mainly has garnet?calcite?quartz and anorthose,secondly has a little epidote?chlorite and sericite,etc.The ore body of Erdaohe lead-zinc silver deposit mainly hosted in Middle-Lower Ordovician Duobaoshan Formation and Middle and Upper Ordovician Luohe Formation stratums, which compose 0-300 meters external contact zone with late Jurassic diorite and early Cretaceous granite porphyry intrusive body, ore-hosted rocks mainly are skarn?Skarnized carbonatite and Skarnized metamorphic sandstone(powder),etc,deposit type belongs to Contact-metasomatic(skarn) deposit.The ore-forming geological body of the deposit is Early Cretaceous granite porphyry, the weighted average age results were 126.7±0.7Ma-133.7±1.2Ma. Ore-forming structure mainly developed in Duobaoshan Formation and Luohe Formation stratums,following lithology interface with different physical properties and interlayer fracture zone in competent strata rocks because of northeast axial homoclinal anticline fold structure in the workspace; mineralize structural surface mainly is silico-calcium surface. Alteration mineral assemblage are garnet?diopside skarn minerals(skarn stage of mineralization) in early stage,ect, metallogenic stage main are chlorite,epidote,Pyrite, Silicide, Sericite, Kaolinite(Quartz- sulfide stage of mineralization),ect,having typical silico-calcium surface mineralization feature.The research demonstrated that No. 1 ore block of main ore body(?region) still has greater ore potential towards deep,also extending to southwest of ?region, number ? region where is west southwest of No. 1 main orebody should exist north west ore body with conjugated north east ore body. Based on established ore prediction geologic model in the workspace, delineated prospecting target outside known ore body in the west side of south in the workspace.